From the BBC web page Food
Turkish delight
450g/1lb granulated sugar
1 lemon, juice only
550ml/19½fl oz water
75g/3oz cornflour
1 tsp cream of tartar
3 tbsp rosewater
3 tbsp icing sugar, plus extra for dusting
110g/4oz dark chocolate, 85 per cent cocoa solids, melted
For the Turkish delight, line a 23cm/9in square deep baking tray with baking parchment.
Place 350ml/12½fl oz of the water, the cornflour and cream of tartar into a separate pan and whisk together well. Place over a medium heat and cook until the mixture has thickened.
Meanwhile, place the sugar and the remaining 200ml/7fl oz water and the lemon juice into a pan and place over a medium heat. Bring to the boil and heat to 240C/465F (you will need a sugar thermometer).
When the sugar and water mixture has reached 240C/465F, add the cornflour mixture and whisk vigorously to combine. Return to the heat and cook over a low heat for 20-30 minutes, until thickened and light golden-brown.
Remove from the heat, add the rosewater and stir well.